Β-lactam allergy

Beta-lactam allergies

Cross-reactivity

	C-7 G1	C-7 G2	C-7 G3	C-3 G1	C-3 G2	C-3 G3	C-3 G5	C-3 G6	C-3 G7
Penicillin	X
Ampicillin		X
Amoxicillin		X
Cefazolin
Cephalexin		X		X
Cefadroxil		X		X
Cephalothin	X					X
Cefotetan					X
Cefoxitin	X						X
Cefuroxime							X
Cefaclor		X
Cefotaxime			X			X
Ceftriaxone			X
Ceftazidime									X
Cefixime								X
Cefdinir
Cefipime			X
Ceftaroline

C-7 Side Chains

Group 1: penicillin, cephalothin, cefoxitin
Group 2: amoxicillin, ampicillin, cefaclor, cephalexin, cefadroxil
Group 3: cefipime, cefotaxime, ceftriaxone

C-3 Side Chains

Group 1: cefadroxil, cephalexin
Group 2: cefotetan
Group 3: cefotaxime, cephalothin
Group 4
Group 5: cefuroxime, cefoxitin
Group 6: cefixime
Group 7: ceftazidime

Comparison of R1 and R2 structural similarities between b-lactam drugs

Drugs that have identical R1 or R2 structures are listed as R1 (red cell) or R2 (gold cell). If only the ring or branch chain moiety of the R1 structure is identical, it is listed as R10 or R100, respectively. Drugs that have similar R1 or R2 structures are listed as r1 or r2. If only the ring or branch chain moiety of the R1 structure is similar, it is listed as r10 or r100, respectively. Blank cells imply no R1 or R2 structural similarities.

Hypersensitivity Reactions

Type I (IgE-mediated)
- Anaphylaxis
- Itchy rash
- Penicillins should be avoided
Type II (IgG-mediated)
- Non-itchy rash
- Rash will improve if treatment continues, no need to avoid penicillins
Type IV (cell-mediated)
- Toxic epidermal necrolysis
- Stevens-Johnson syndrome
- Penicillins should be avoided